Dataset Information

Susceptibility Testing by Volatile Organic Compound Detection Direct from Positive Blood Cultures: A Proof-of-Principle Laboratory Study.

ABSTRACT:

Background

Bacteria produce volatile organic compounds (VOCs) during growth, which can be detected by colorimetric sensor arrays (CSAs). The SpecifAST^® system (Specific Diagnostics) employs this technique to enable antibiotic susceptibility testing (AST) directly from blood cultures without prior subculture of isolates. The aim of this study was to compare the SpecifAST^® AST results and analysis time to the VITEK^®2 (bioMérieux) system.

Methods

In a 12-month single site prospective study, remnants of clinical positive monomicrobial blood cultures were combined with a series of antibiotic concentrations. Volatile emission was monitored at 37 °C via CSAs. Minimal Inhibitory Concentrations (MICs) of seven antimicrobial agents for Enterobacterales, Staphylococcus, and Enterococcus spp. were compared to VITEK^®2 AST results. MICs were interpreted according to EUCAST clinical breakpoints. Performance was assessed by calculating agreement and discrepancy rates.

Results

In total, 96 positive blood cultures containing Enterobacterales, Staphylococcus, and Enterococcus spp. were tested (269 bug-drug combinations). The categorical agreement of the SpecifAST^® system compared to the VITEK^®2 system was 100% and 91% for Gram-negatives and Gram-positives, respectively. Errors among Gram-positives were from coagulase-negative staphylococci. Overall results were available in 3.1 h (±0.9 h) after growth detection without the need for subculture steps.

Conclusion

The AST results based on VOC detection are promising and warrant further evaluation in studies with a larger sample of bacterial species and antimicrobials.

SUBMITTER: Kuil SD

PROVIDER: S-EPMC9220186 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature

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Publications

Susceptibility Testing by Volatile Organic Compound Detection Direct from Positive Blood Cultures: A Proof-of-Principle Laboratory Study.

Kuil Sacha Daniëlle SD Hidad Soemeja S Schneeberger Caroline C Singh Pragya P Rhodes Paul P de Jong Menno Douwe MD Visser Caroline Elisabeth CE

Antibiotics (Basel, Switzerland) 20220524 6

<h4>Background</h4>Bacteria produce volatile organic compounds (VOCs) during growth, which can be detected by colorimetric sensor arrays (CSAs). The SpecifAST<sup>®</sup> system (Specific Diagnostics) employs this technique to enable antibiotic susceptibility testing (AST) directly from blood cultures without prior subculture of isolates. The aim of this study was to compare the SpecifAST<sup>®</sup> AST results and analysis time to the VITEK<sup>®</sup>2 (bioMérieux) system.<h4>Methods</h4>In a ...[more]

PMID: 35740111

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Project description:Drought stress is a major constraint on crop production. While Trichoderma fungi are widely recognized for enhancing plant tolerance to abiotic stresses, the fungal molecules responsible for these protective effects remain poorly defined. In this study, we investigated the role of 6-pentyl-a-pyrone (6PP), a volatile compound produced by diverse Trichoderma spp., in modulating plant responses to water deficit. Dwarf bean (Phaseolus vulgaris) seedlings grown from seeds coated with a carrier polymer delivering 6PP were significantly more tolerant to drought stress than seedlings from seeds coated with the polymer alone (control), exhibiting increased leaf area, root length, chlorophyll content, and photosynthetic rate. To elucidate the mechanisms induced by this molecule, comparative transcriptome analyses were performed in the presence and absence of 6PP under both wellwatered and drought conditions; only 49 DEGs were detected under wellwatered conditions. In contrast, 476 expressed genes were identified in drought-stressed plants grown from 6PP-coated seeds, indicating substantial transcriptional reprogramming. 6PP treatment reprogrammed stress-responsive gene networks, including pathways associated with photosynthesis, carbohydrate metabolism, phosphorylation-mediated signaling, defense responses, and oxidative stress regulation. In addition, drought-stressed plants treated with 6PP exhibited enhanced MAPK phosphorylation, providing protein-level evidence for activation of phosphorylation-mediated signaling pathways associated with stress tolerance. Functional enrichment analyses further highlight secondary metabolite pathways, including those for phenylpropanoid and flavonoid biosynthesis, suggesting enhanced production of protective compounds and maintenance of photosynthetic activity under drought stress. Several stress-related genes were modulated prior to drought exposure, indicating a possible priming effect. Collectively, our findings identify 6PP as a potential signaling molecule contributing to enhanced drought resilience and provide new insights into the molecular basis of Trichoderma-mediated stress protection.

Dataset Information

Susceptibility Testing by Volatile Organic Compound Detection Direct from Positive Blood Cultures: A Proof-of-Principle Laboratory Study.

Background

Methods

Results

Conclusion

Publications

Susceptibility Testing by Volatile Organic Compound Detection Direct from Positive Blood Cultures: A Proof-of-Principle Laboratory Study.

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